Inkjet printers form a printed image by ejecting or “jetting” small droplets of liquid ink onto an image receiving surface, such as an intermediate transfer surface or a media substrate. The benefits of inkjet printing include low printing noise, low cost per printed page, and the ability to print “full color” images. Inkjet printers include, among other components, a printhead and a printhead controller. The printhead controller selectively sends ejection signals to the printhead that cause ejectors within the printhead to eject droplets of liquid ink upon an image receiving surface to form at least a portion of a printed image.
In general, inkjet printheads include a plurality of ink ejectors and at least one reservoir for storing a quantity of ink. Monochromatic inkjet printheads may include a single reservoir for containing a single color of ink. Full color inkjet printheads may include a plurality of reservoirs, with each reservoir configured to contain a different color of ink. For instance, a full color inkjet printhead may include four reservoirs with each reservoir containing one of the four colors of ink typically used to generate full color images; namely, cyan, magenta, yellow, and black. The ink ejectors eject very small droplets of the ink onto an image receiving surface. Often, a group of one hundred to six hundred individual ink ejectors are coupled by a manifold to a single ink reservoir. Specifically, a monochromatic printhead may include a single group of ink ejectors fluidly coupled to the single reservoir, while a full color printhead may include a separate group of ink ejectors for each of the reservoirs. Thus, a full color printhead having four reservoirs may have four groups of ink ejectors, each of which is fluidly coupled to a different ink reservoir.
An ink reservoir of an inkjet printhead may include a reservoir vent that permits air to enter and exit the reservoir. The vent allows air to be expelled from the reservoir in response to the reservoir being filled with ink. Additionally, the vent enables air to enter the reservoir as ink is ejected by the ink ejectors. Therefore, ink reservoir vents operate to equalize air pressure within the ink reservoir.
Typically, reservoir vents include a vent opening positioned in a region of the ink reservoir located above a maximum ink level. At times, however, a printer may be moved or repositioned. These movements may allow ink within the reservoir to migrate to the vent opening and be spilled from the reservoir. The spilled ink, as a consequence, is lost for printing and may contact parts of the printer not designed for ink contact. Therefore, more inkjet reservoir venting solutions are desirable.